Method of and apparatus for actuating the torque transmitting system and the transmission in the power train of a motor vehicle

ABSTRACT

The friction clutch between the engine and an automated transmission in the power train of a motor vehicle are operated and controlled by an actuator which effects changes in the extent of engagement of the clutch as well as the selection of and shifting into particular gears. The actuator forms part of a unit which receives a pressurized hydraulic fluid from a source including an accumulator and a proportional valve which latter selects the fluid pressure necessary to shift the transmission into a selected gear.

BACKGROUND OF THE INVENTION

The invention relates to a motor vehicle with an engine, a transmissionand torque transmitting system which is disposed in the path of torquetransmission between the engine and the transmission, with an actuatingunit for the initiation of the clutching operation and of the shiftingand selecting operation for the carrying out of an automated change ofgear.

The carrying out of a change of gear in motor vehicles is performed inpart manually by the driver, and such change of gear is carried out byhand by means of an actuating lever, such as a shifting lever.

There also exist automatic transmissions which, in comparison with ashift transmission, such as a range transmission, are of a morecomplicated and more expensive design entailing a considerable increasein the cost of the transmission. Such automatic transmissions can carryout an automatic change of gear in response to hydraulic actuation ofbrakes and clutches.

OBJECTS OF THE INVENTION

The object underlying the invention is to provide an automated shifttransmission which carries out a gear change in a range transmission inresponse to a command from the driver or in a fully automatic way.Another object underlying the invention is to render it possible to putto use those transmissions which are employed as manually actuated shifttransmissions to operate as automated shift transmissions, preferablywith only minor changes or without changes.

Another object is to provide an actuator for the carrying out of theshifting, selecting and clutching operations which actuator permits aconvenient change of gears but is nevertheless optimized as far as thenumber of its parts is concerned and can be produced at a reasonablecost.

A further object is to provide an integrated actuator which essentiallyencompasses the required adjusting means and sensors.

SUMMARY OF THE INVENTION

In accordance with the invention, this is accomplished in that anactuating unit is supplied with a pressurized medium by a hydraulic unithaving a hydraulic pump and, if necessary, an accumulator, to effect aplanned initiation of a gear shifting operation. The actor unitcomprises at least one adjusting member, and the hydraulic unitcomprises valves and connections for hydraulic fluid which are actuatedto effect a controlled initiation of the shifting and selectingoperation. The hydraulic connections are provided primarily between thevalves, respectively between the valves and the adjusting members.

In accordance with the invention, this can also be accomplished in thatthe actuating and hydraulic unit comprise a first section wherein aproportional valve selects a fluid pressure for shifting by means of anadjusting member and at least one valve which is installed downstream ofthe proportional valve selects the direction of shifting, and a secondsection wherein a proportional valve selects a fluid pressure for theactuation of the torque transmitting system by means of an adjustingmember and, if necessary, for the selection by means of an adjustingmember, at least one valve which is installed downstream of theproportional valve being utilized to initiate the selection.

It can be of advantage if the actuating unit and the hydraulic unit forma structural entity; however, the hydraulic pump and/or the accumulatorneed not necessarily belong to such structural entity but can be mountedseparately.

It can also be of advantage if the actuating unit and the hydraulic unitare mounted separately and are connected to each other by fluidconduits. Thus, a valve block can be installed separately of anactuating block with adjusting members. Still further, it can be ofadvantage if the adjusting member for the actuation of the clutch is notinstalled in the actuating unit. The sensorics can be received in ormounted on the actuating unit or in a hydraulic unit or at the adjustingmembers. The member for the actuation of the clutch can be directlyconnected with the valve block. Furthermore, a piston which isinterposed for example for liquid separation or for monitoring theactuation of the clutch can be installed between the adjusting memberand the valve block.

Still further, it can be of advantage if the actuating unit and/or ahydraulic unit contains or comprises those adjusting members and valvesand hydraulic fluid connections which must be actuated for thecontrolled carrying out of the shifting and selecting operations.Analogously, it can be of advantage if the actuating unit and/or thehydraulic unit comprises at least one valve which is actuated toinitiate the disengagement of the torque transmitting system, a fluidconveying connection being established between a clutch slave cylinderwhich is disposed in the region of the clutch and the at least one valvewhich is disposed in the actor.

Basically, it can be of advantage if the actuating unit and/or thehydraulic unit contains at least one sensoric unit which monitors theclutch actuating movements and/or the gear shifting or gear selectingmovement. The arrangement can be such that the sensoric unit of theactuating unit can monitor the gear shifting and selecting operations,and the sensoric unit of the hydraulic unit monitors the clutchactuating operation.

Furthermore, it can be of advantage to provide in the actuating unit atleast one sensoric unit for the monitoring of the gear shifting andselecting operation. Analogously, it can be of advantage if a firstsensoric unit for the monitoring of the clutch actuating movement and asecond sensoric unit for joint monitoring of the gear shifting andselecting movements are integrated into or received in the actuatingunit and/or in the hydraulic unit and/or in a fluid connection. It canbe of particular advantage if discrete sensoric units are respectivelyintegrated into the hydraulic unit to monitor the clutch actuatingmovements, and into the actuating unit to monitor the gear shifting andselecting movements.

Moreover, it can be of advantage in an embodiment of the novel actuatorto employ, for the actuation of each of the adjusting members forclutching, gear shifting and gear selection a discrete proportionalvalve and, if necessary, a relay valve installed downstream of therespective proportional valve.

In accordance with the invention, it can be of advantage if, for thepurposes of actuating the adjusting members for the clutching, gearshifting and/or gear selection, the actuation of at least one of theadjusting members involves the utilization of a proportional valve and,if necessary, relay valves downstream of the proportional valve.

It can also be desirable if, in connection with the actuation ofadjusting members for clutching, gear shifting and/or gear selection, aproportional valve and, if necessary, a relay valve downstream of theproportional valve are provided for the actuation of at least oneadjusting member and at least one relay valve is utilized for theactuation of at least one other adjusting member.

It can be particularly advantageous if at least one proportional valveis employed for the actuation of each of the adjusting members for theclutching, gear selection and gear shifting, it being preferred toutilize a first proportional valve for the clutching and gear selectionand another proportional valve for gear shifting and to install, ifnecessary, relay valves downstream of such proportional valves.

Furthermore, it can be of advantage if a proportional valve regulatesthe pressure for the transmission of transmissible torque by the clutchand, once the clutch is disengaged, to employ at least one downstreamrelay valve to also regulate the gear selecting operation with thepressure which has been selected by the proportional valve. Theregulation of the gear selecting operation exhibits the advantage thatit is not absolutely necessary to employ regulated valves for the gearselecting operation. By resorting to energy storing elements which areprovided in the transmission, and by relying upon the resultingapplication of force to the transmission actuating element, such as forexample, the central shifting shaft, one can achieve a controlledactuation by the adjusting members against the action of the force.

Basically, it can be of advantage in a further embodiment if, for thepurposes of initiating he gear selecting operation, a proportional valveregulates the pressure of the hydraulic fluid and two plenum chambers ofa differential cylinder are controlled by two relay valves installeddownstream of the proportional valve.

In accordance with a further inventive concept, it can be of advantageif, for the purposes of selection, the relay valves control the twoplenum chambers of the differential cylinder in such a way that bothplenum chambers contain a pressurized fluid or neither of the plenumchambers contains a pressurized fluid or the first plenum chambercontains a pressurized fluid while basically no pressure is maintainedin the second plenum chamber or the pressure in the first plenum chamberis basically nil but the second plenum chamber contains a pressurizedfluid.

Furthermore, it can be of advantage if the pressure in the two plenumchambers of the differential cylinder is controlled in such a way thatone establishes a multistage characteristic for the selection of thegear ratios.

Still further, it can be of advantage if, for the purposes of shifting,a differential cylinder is controlled by a proportional valve and arelay valve installed downstream of the proportional valve. In thisconnection, it might be desirable if, for the purposes of gear shifting,the at least one proportional valve controls or regulates at least onecylinder pressure.

It can be of particular advantage if at least one proportinal valve is aproportional directional control valve. It can also be of advantage if aproportional valve is a pressure feedback type proportional pressurereducing valve. In this connection, it can be of advantage if the gearselecting operation or the gear shifting operation is initiated with aproportional pressure reducing valve. It can equally be of advantage ifthe actuation of the clutch is initiated by a proportional directionalcontrol valve. A combined initiation of the clutch actuation and of thegear selecting operation is preferably carried out with a proportionalpressure reducing valve.

Basically, it can be of advantage if, for the purposes of initiating thegear shifting operation, the two plenum chambers of the differentialcylinder are supplied with pressurized fluid by regulating orcontrolling the pressure in such a way that there develops apressure-regulated or pressure-controlled force for shifting in onedirection or in another direction. In this connection, it can be ofparticular advantage if the magnitude of the pressure-regulated orpressure-controlled force acting in the one direction matches that ofthe pressure-regulated or pressure-controlled force acting in the otherdirection.

It is of advantage to design one embodiment of the invention in such away that the relay valve which initiates the gear shifting operation ofthe transmission subjects the first plenum chamber of the differentialcylinder to the action of pressurized fluid while the fluid in the otherplenum chamber is not pressurized or that both plenum chambers contain apressurized fluid.

Furthermore, it can be of particular advantage if at least one of thedifferential cylinders for gear shifting or gear selection contains apiston having opposite sides with axially oriented effective surfaces ofdifferent sizes. In this connection, it might be of additionalconsiderable advantage if at least one of the differential cylinderswhich are utilized for the gear shifting and gear selection contains apiston having opposite sides with axially oriented effective surfaces ofdifferent sizes with a surface ratio of 2:1.

In accordance with an advantageous embodiment of the invention, it canbe of particular advantage if at least one of the proportional valves isa pressure regulated, particularly a load feedback regulated,proportional valve.

It can be of advantage if at least one of the proportional valves is apressure regulated, particularly a load feedback regulated, proportionalvalve and at least one further proportional valve is a proportionaldirectional control valve.

Basically, it can be of advantage if at least one of the proportionalvalves, namely a proportional valve for clutching and gear selection anda proportional valve for gear shifting, is a pressure regulated valve,particularly a load feedback valve.

Furthermore, it can be of advantage in accordance with an embodiment ofthe invention if the clutch actuating operation is regulated as afunction of the extent of movement and/or pressure or is controlled as afunction of pressure.

Furthermore, it can be of advantage if the gear selecting operation isregulated as a function of the extent of movement and/or pressure or iscontrolled as a function of pressure.

In accordance with a further embodiment of the invention, it is ofadvantage if the gear shifting operation is controlled or regulated as afunction of the extent of movement, and to carry out an additional,slave, pressure regulation or pressure control, particularly in thecourse of the synchronization stage of the gear shifting operation.

It is of advantage if the gear shifting operation is controlled orregulated as a function of pressure.

Furthermore, it can be of advantage if the differential cylinders forthe selection or shifting are operated by relay valves and the fluidpressure for the shifting or selection is controlled or regulated bymeans of proportional valves upstream of the relay valves. Theproportional valves which are installed in the path of fluid flowupstream of the relay valves exhibit the novel advantage that they canbe designed for a lower rate of fluid flow therethrough and the relayvalves must be designed for a higher volumetric flow. This renders itpossible to employ relatively inexpensive proportional valves and thisadvantage is not cancelled by potential higher cost of the relay valves.On the other hand, if the proportional valve is located in the path offluid flow downstream of the relay valve, as considered in a directiontoward the consumer, the proportional valve must be designed for thehigh volumetric flow.

In accordance with an advantageous embodiment of the invention, it isdesirable if the controlled or regulated fluid pressure for actuation ofthe clutch is also put to use to actuate the gear selecting cylinder.

Moreover, it can be of particular advantage if the fluid pressure forthe initiation of the gear selecting operation is monitored in thehydraulic layout or in the hydraulic unit downstream of the proportionalvalve which controls the clutch.

It can equally be of advantage if the fluid pressure for actuation ofthe gear selecting cylinder, such as for the initiation of the gearselecting operation, is generated by a discrete pressure regulatingvalve, especially a load pressure feedback regulating valve.

In accordance with another inventive concept, it is advantageous if avehicle comprises an engine, a transmission, such as a rangetransmission, and a torque transmitting system, such as a clutch, in thetorque transmitting path between the engine and the transmission, acentral control unit and a hydraulic unit with a hydraulic pump and, ifnecessary, with an accumulator and valves and an actuating unit, such asan actuating unit, which can comprise adjusting members and, ifnecessary, valves for the initiation of the selection of and shiftinginto a gear ratio in the shifting categories of the transmission, and anadjusting member serving to control the clutch and being controlled insuch a manner that the actuation of the adjusting members takes place atleast in part serially.

It can be of advantage if the clutch actuation (K), the shiftingoperation (S) and the selecting operation (W) take place at least inpart serially. It can be desirable if the procedure K-S-W-S-K takesplace entirely serially or the operation K-S and/or S-K, as well aspossibly S-W and W-S, take place at least in part in parallel, such asat the same time.

Furthermore, it can be of particular advantage if the hydraulic unitand/or the actor unit for the initiation of the shifting and selectingoperations and for actuation of the clutch can be provided on, such asattached to, as auxiliary equipment, a normally manually operated rangetransmission.

In accordance with a further inventive concept, it is of particularadvantage in relation to a sensoric unit if the latter is equipped witha movable means and a fixedly mounted means, the movable meanscomprising a transmitter and the fixedly mounted means monitoring theposition of the movable means relative to the fixedly mounted means, thesensoric unit being disposed at/in an actuating unit to directly orindirectly monitor the movement of an element of the transmission in thecourse of a gear selecting or gear shifting operation.

Still further, it can be of advantage if the movable means is movableunidimensionally or twodimensionally or threedimensionally.

An embodiment is preferably designed in such a way that the movablemeans is movable in a plane or on an arcuate surface, such as forexample, the external surface of a cylinder.

Furthermore, it can be of advantage if the movable means is movablealong a straight or curved path.

Moreover, it can be of particular advantage if the sensoric unitmonitors the position of the movable means in a contactless fashion oras a result of contact.

Moreover, it can be of advantage if the fixedly mounted means comprisesa spatial arrangement of sensors which generate signals in dependencyupon the position of the movable means.

Moreover, it can be of advantage if the fixedly mounted means comprisesat least one sensor which generates a signal in dependency upon theposition of the movable means.

Still further, it can be of advantage if the fixedly mounted meanscomprises a spatial array of Hall generators or other contactlesssensors.

Furthermore, an embodiment of the invention can advantageously bedesigned in such a way that the fixedly mounted means comprises arectangular or square or triangular or linear array of at least two Hallgenerators or other contactless sensors.

Accordingly, it is desirable that the movable means comprise at leastone magnet or another contactless transmitter.

It can be of advantage if the contactless sensors or Hall generators aredisposed on a plane or on an arcuate surface or in a straight or arcuatepath.

Accordingly, it can be desirable that the fixedly mounted means is atrack or a surface of a potentiometer and the movable means is a slidingcontact of a potentiometer.

It can be of advantage if the movable means is a track or a surface of apotentiometer and the fixedly mounted means is a sliding contact of apotentiometer.

In accordance with a further modification of the invention, it can be ofadvantage that, based on the signals generated by the sensors, thecontrol unit ascertains the position the movable means assumes relativeto the fixedly mounted means, particularly for the detection of anactual shifting and/or selecting stage and/or for the basicallycontinuous monitoring of the means which are provided to perform theshifting and/or selecting operation.

It can be of advantage if the control unit transforms the signals fromthe individual sensors into a matrix representation, the analog signalsfrom the sensors being converted into digital values and each positionwhich the movable means assumes as well as the path of the movable meansis quasi continuously represented by the matrix values.

In accordance with the invention, it can be desirable that the controlunit provide, for each position of the movable means, a matrix valuewhich is formed by the individual measurement values of sensor signalsfrom the individual sensors.

Furthermore, it can be of advantage if a twodimensional resolution ofthe sensoric unit is carried out by a spatial arrangement of basicallyunidimensionally acting sensors.

In accordance with a further inventive concept, it can be of advantagein connection with a method for the regulation or control of anautomated shift transmission, such as a range transmission with acontrol unit, an actuating arrangement and sensors for the detection ofthe operating condition, if the initiations of the clutching operationand of the gear selecting operation take place serially, it beingpreferred to employ a common pressure regulating valve.

Furthermore, it can be of advantage if the initiations of the clutching,shifting and selecting operations take place serially.

Still further, it can be of advantage that the initiation of theshifting operation take place independently of the serial initiation ofthe clutching and selecting operations.

It is of particular advantage that the shifting operation and the serialclutching and selecting operations take place simultaneously, at leastin part.

In accordance with a further inventive concept, it is of advantage if,in a method of automatically shifting gears in range transmissions, achange of gear is initiated in response to depression of a knob, such asmanually, or in a fully automatic way.

In accordance with a further inventive concept, it can be of particularadvantage if, depending upon the position of the switch, a change ofgear take place in a highly comfortable manner and in a particularlysporty manner as a result of shifting in accordance with a driver'sdesire.

In this connection, it can be of advantage that, in the course of acomfortable gear shift, the synchronizing operation during shifting canbe carried out with a force smaller than that required for a comfortablesporty gear shift.

In accordance with a further inventive concept, it is of advantage if amotor vehicle having an engine, a transmission and a torque transmittingsystem, such as a clutch, in the torque transmitting path between theengine and the transmission, with a hydraulic unit which comprises ahydraulic pump and at least one valve for the actuation of a hydrauliccylinder serving to control the torque which can be transmitted by theclutch along an actuating path, such as a disengagement path, isdesigned in such a way that the disengagement movement of the clutch ismonitored by an arrangement which is installed in a fluid-conveyingconnection to the adjusting member for the clutch and comprises a pistonwhich denotes the disengaging movement or the stage of disengagement byits position relative to a sensor.

Furthermore, it can be of advantage to provide an arrangement with apiston which is axially movable in a housing and, if necessary, isspring biased at least at one of its sides and, if necessary, suchsprings are installed in the housing, a pressurizable chamber beingprovided ahead of and behind the piston as seen in the axial directionand being provided with hydraulic connections, a sensor being providedto monitor the axial position of the piston. A controlled actuation ofthe clutch effects an axial displacement of the piston, such as a sensorpiston.

Furthermore, it can be of advantage if an arrangement is assembled insuch a way that the arrangement is provided with a housing and a plenumchamber at the input side as well as a plenum chamber at the outputside. An axially displaceable piston separates the two plenum chambersfrom each other and the arrangement is disposed in a fluid connection.An actuation of a downstream adjusting member brings about an axialdisplacement of the piston and a sensor, which is provided at or in thehousing, monitors such movement of the piston.

It can be of advantage to provide in the housing energy storing elementswhich act upon the piston in the axial direction and center it in theunpressurized condition.

Furthermore, it can be of advantage to provide the housing with asnifting bore for a planned pressure equalization, such snifting borecommunicating with the sump of the hydraulic unit by way of a fluidconnection.

Still further, it can be of advantage if a sensor for the monitoring ofthe position of the clutch is a contactless sensor, such as for examplea Hall generator.

It can also be of advantage if the displacement of the disengagingbearing of a clutch is monitored by a resiliently flexible means whichextends into the transmission bell from the outside and abuts thedisengaging bearing essentially in the axial direction, the bending ofthe flexible means being monitored by a sensor.

In this connection, it can be of advantage if the resiliently flexiblemeans is clamped, such as held, in a base plate and such base plate issecured to the exterior of the transmission.

Furthermore, it can be of advantage if the sensor is a strain gauge or apiezoelectric sensor or another contactless sensor, such as a Hallgenerator.

In accordance with a further inventive concept, it can be of advantageif a throttle valve or a flow restrictor is installed upstream of therelay valves for the initiation of a gear selecting operation.

It can equally be of advantage if a throttle valve or a flow restrictoris installed downstream of an accumulator.

Moreover, it can be of advantage to provide a throttle valve or a flowrestrictor in a conduit for a pressurized fluid, such as a hydraulicconduit.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in greater detail with reference to theFIGS. 1 to 29. There are shown in:

FIG. 1 a schematic representation of a vehicle,

FIG. 2 a schematic representation of an automated shift transmission,

FIG. 2a a view of an actuator,

FIG. 3 a view of an actuator,

FIG. 4 a view of an actuator,

FIG. 5 a sectional view of an actuator taken in the direction of thearrows 5--5 of FIG. 3,

FIG. 6 a view of an actuator,

FIG. 7 a view of an actuator,

FIG. 8 a view of an actuator,

FIG. 9 a view of an adjusting member,

FIG. 10 a view of an adjusting member,

FIG. 11 a view of a sensor arrangement,

FIG. 12 a view of a shifting scheme,

FIG. 13 a hydraulic diagram,

FIG. 14 a hydraulic diagram,

FIG. 15 a hydraulic diagram,

FIG. 16 a diagram,

FIG. 17 a hydraulic diagram,

FIG. 18 a hydraulic diagram,

FIG. 19 a hydraulic diagram,

FIG. 20 a hydraulic diagram,

FIG. 21a a view of an actuator,

FIG. 21b a view of an actuator,

FIG. 21c a view of an actuator,

FIG. 22 a block diagram,

FIG. 23 a detail of a hydraulic diagram with a sensor piston,

FIG. 24 a diagram,

FIG. 25 a sectional view of a transmission bell,

FIG. 26 a sensor,

FIG. 27 a hydraulic diagram,

FIG. 28 a hydraulic diagram, and

FIG. 29 an actuator block.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 shows a vehicle 1 with a driving unit 2, such as a combustionengine, with a torque transmitting system 3 and a following transmission4. The drive shaft or cardan shaft 5 is driven by the transmission 4 andis coupled with the drive shafts 7 and with the driven wheels 8 by wayof a differential 6. The torque transmitting system 3 consistsessentially of a flywheel 3a, a clutch disc 3b, a diaphragm spring 3c, aclutch cover and a disengaging mechanism 3d. The disengaging mechanism3d can consist of a hydraulic central disengaging member or of amechanical disengaging member with mechanical actuation, such as adisengaging member with a disengaging fork, the actuation of themechanical disengaging lever, such as a disengaging fork, beinginitiated by a slave cylinder. In FIG. 1, there is shown a disengagingbearing 9 which is actuatable by way of a disengaging fork 10, themovements of the disengaging fork 10 being initiated by a slave cylinder11. As shown, the torque transmitting system 3 can constitute a frictionclutch with or without an adjusting mechanism which compensates forwear. Furthermore, the torque transmitting system can constitute amagnetic powder clutch or the bypass clutch of a hydrokinetic torqueconverter.

The transmission 4 is a conventional shift transmission comprisinginternal shifting elements and being shifted by way of a centralshifting shaft 12 or shifting rods. The transmission can be designed asa transmission with an interruption of pulling force.

The embodiment of FIG. 1 comprises an actuating unit 13, such as anactuator unit, which includes a hydraulic or hydrostatic block, ifnecessary with valves and hydraulic fluid conduits and adjustingcylinders which carry out an actuation of the transmission operatingelement 12. The actuating unit 13, such as an actuator unit, can also beconnected with a hydraulic unit 14 which comprises a hydraulic aggregatewith a hydraulic pump and a tank and/or a reservoir, such as anaccumulator. The hydraulic unit 14 can be divided into several subunitswhich can be installed in advantageus positions in the vehicle dependingupon the required space therefor.

The hydraulic unit 14 can be divided into subunits. For example, thesubunit including a hydraulic pump with motor can be replaced with ahydraulic pump which is provided in the vehicle in such a way that acommon hydraulic pump services several hydraulic elements. For example,such a pump can constitute a pump of the power steering mechanism.

Analogously, the actuating unit 13 and the hydraulic unit 14 canconstitute a structural unit. However, in such instance and ifnecessary, at least some discrete adjusting members, such as for examplefor actuation of the clutch, and discrete hydraulic elements, such asfor example a pump, cannot be integrated into the hydraulic unit.

Furthermore, there is made available a control unit 15 with a centralcomputer unit which processes the incoming signals and transmits controlsignals to the actuating arrangement 13 and/or to the hydraulic unit 14with the adjusting members. For example, the control unit 15 cancomprise a central computer unit which initiates, in dependency upon theoperating point, the control of the clutch actuation and the actuationof the transmission, such as the automated gear change of thetransmission 4.

The control unit 15 is in signal transmitting communication withsensors, such as for example a throttle valve sensor 16, the throttlevalve 17 of the driving aggregate 2, as well as with RPM sensors 18,tachometer sensors 19 and gear recognition sensors which can beinstalled, for example, in the actuating unit 13. The control unit 15further comprises a CAN bus interface by means of which the control unitis in signal transmitting communication with other control units sothat, for example, the engine electronics can transmit to the controlunit signals denoting the engine torque.

The FIG. 2 shows the transmission 4, the torque transmitting system 3,such as a friction clutch, with a flywheel 3a, the clutch disc 3b, thediaphragm spring 3c, the clutch cover 3e and a hydraulic centraldisengaging member 20. The hydraulic central disengaging member 20 issupplied with hydraulic fluid and fluid pressure by a supply conduit 21,such as a compressed fluid conduit, which is operatively connected tothe actuating unit 13. The actuating unit 13 is secured to thetransmission 4 and receives at least the end portion of the centralshifting shaft of the transmission so that the internal adjustingmembers of the actuating unit can move the shifting shaft of thetransmission in the axial direction as well as in the circumferentialdirection whereby the central shifting shaft can be moved or actuated inaccordance with an H- or double-H gear shifting scheme in order toselect the required gear positions within the transmission. In thismanner, one can initiate an automated gear change.

The actuating unit 13 is in signal transmitting communication with thecontrol unit 15 by at least one data transmitting conduit 21 which, ifdesired, can constitute a harness with various data transmitting andcurrent conveying conduits. There is further shown the CAN-bus interface22 as well as a current source 23 which supplies current/voltage to thecontrol unit 15 and to the actuating unit 13.

The hydraulic unit 14 of FIG. 1 is divided in FIG. 2 into two subunitsof which the subunit 24 encompasses the hydraulic aggregate with pump 25and the electric motor 26 for the pump. The further subaggregate isconstituted by the tank- and accumulator unit 27 which includes apressure accumulator 28 and a pressure relief valve 29 as well as asensor 30 which monitors the pressure conditions in the pressureaccumulator to start the hydraulic pump when the pressure drops below athreshold value in order to reestablish the optimum pressure conditionswithin the accumulator, or to again turn off the hydraulic pump when apreselectable upper threshold is exceeded. The unit 27 is connected withthe actuating unit 13, such as an actuator unit, by way of hydraulicconduits 31, 32 so that the actuation of the clutch as well as theselection of gears and shifting of the transmission can be carried outin an automated manner by way of valves which are provided in actuatingunit and, if necessary, by way of adjusting members. The actuation iscarried out in response to a planned actuation of valves for theapplication of pressure to the adjusting members by resorting to atleast one piston-cylinder unit. FIG. 2 further shows a cardan shaft 33which is installed at the output side and which transmits torque to thedriven shafts.

FIG. 2a is an elevational view of an actuating unit 13, such as anactuator unit, and of the transmission 4 as seen from the locus of thecardan shaft, the large circle 34a denoting the envelope of thetransmission bell 34. Furthermore, the basically rectangular outline 35is established by the outline of the transmission proper, and theactuating unit 13 is flanged, e.g., screwed, basically in the region ofthe central shifting shaft and surrounds or encompasses the cardan shaft33, at least in part. In this embodiment, the actuator unit, such as theactuating unit 13, is preferably designed in such a way that it can beinstalled in the cardan tunnel of a vehicle but, if the situation, asconcerns the available space, is altered, the actuating unit 13 can alsobe constructed in a different way.

FIG. 3 is a side elevational view of the actuator 13, such as theactuating unit which is illustrated in FIG. 2a, there being shown thesecuring openings 50 which are provided in the carrier plate 50a andthrough which the actuator can be secured to the transmission. There isfurther shown a plug 51 in a side elevational view, as well as aproportional valve 52, also in a side elevational view. The centralshifting shaft is disposed at the central region of the actuator andextends into the actuator from the rear side because it projects fromthe transmission. The actuator is properly mounted on the transmissionand can thus be designed as an add-on solution. The transmission is aconventional shift transmission as known from the art wherein theconnection for the shifting lever was removed or was not installed andthe actuating 13 is provided to serve as an instrument for automatedgear selection. The region 53 within the actuator is taken up by relayvalves, and the region 54 is taken up by at least one clutch movementsensor.

The actuating unit, such as actuating unit 13, contains all of therelay- and proportional valves as well as all fluid supplying conduitsbetween the valves and possibly sensors and/or adjusting members, suchas adjusting cylinders, which are also received in the housing of theactuating unit, such as actuating unit 13. Furthermore, the actuatoralso encompasses the sensorics for the determination of the gear settingor gear. Under circumstances, the adjusting members or individualadjusting members can also be disposed outside of the actuating unit.

FIG. 3 further shows an extension 55 which forms part of the clutchmovement sensor with sensor piston. This clutch movement sensor is ahydraulically actuated sensor which comprises a housing for a piston andthe movements of the adjusting member take place with the movements ofthe piston. By resorting to a contactless sensor, such as a Hallgenerator, one can monitor the movements or the positions of the piston.As concerns the sensor piston, reference is to be had to FIG. 23.

FIG. 4 illustrates the actuator which is shown in FIG. 3 in a view inthe direction of arrow 4. There is shown the manner in which the centralshifting shaft 60 of the transmission 4 extends into the actuating unit13. At the lower end of the actuator unit 13, there are disposed twoproportional valves 52a, 52b which serve to control or regulate thepressure of fluid in the hydraulic system. In the region 53, there areagain provided relay valves and an adjusting member, such as anadjusting cylinder, is provided in the axial extension 61 of the centralshifting shaft. There is further shown, in a front elevational view, theplug 51 which is secured from the outside by means of screws 51a to thehousing of the actuating unit 13. In an advantageous manner, suchconnection can also be established by means of rivets or snap connectorsor plug-in connectors. The circular margin 62 denotes in section thearrangement of the second adjusting cylinder 61. In the illustratedregion, the adjusting cylinder 61 can cause the central shifting shaftto perform an axial movement or it can initiate such axial movement, theadjusting cylinder 62 being responsible for a rotary movement of thecentral shifting shaft about the axis 63 or it can initiate suchmovement.

The purpose of the bolts 64 and 65 is to ensure that the shaft 66 of theactuator can be connected with the central shifting shaft 60 of thetransmission unit 4 and that the rocker 67 of the linkage for theactuator of the actuating unit 62 is connectable with the axiallyshiftable shaft 66.

FIG. 5 is a sectional view of the actuator in a manner as the latter isshown in FIG. 3, there being further shown the fastening plate 100 withthe openings 50 for attachment of the actuator to the transmission. Thecentral shifting shaft 60 can be seen in a sectional view, the same asthe pin 64 which connects the central shifting shaft 60 with the shaft66 of the actuator. Still further, there is shown a guide sleeve 101which is shiftable in the direction of the axis 103 by means of anadjusting member, such as the adjusting cylinder 102, and is pivotablerelative to the joint 104. In this manner, one achieves that, due toaxial displacement of the piston 105 of the adjusting cylinder 102, theshaft 106 is adjusted in the axial direction and the guide sleeve 101 ispivoted about the shaft 104 so that the connection which is providedwith a spherical head and is installed between the extension 107 of theshaft 66 can be pivoted in response to pivoting of the guide sleeve 101.In this manner, one ensures that, due to an adjustment of the axialposition of the piston 105, the central shifting shaft 60 of thetransmission can be turned about the axis of the central shifting shaft.In lieu of a joint employing a spherical head, one can also employ acardan joint or a universal joint.

Thus, a selection of the axial position of the piston 105 of theadjusting member 102 entails the selection of adjustable angularposition of the central shifting shaft 60. On the guide sleeve 101,there is provided a sensor element 120, such as a transmitter or magnet,which is pivotable in response to pivoting of the element 101. Directlyabove the sensor element 120 there is provided a sensor unit 121, suchas a slave, which is in signal transmitting communication with thecontrol unit 15 by means of the plug 122. For example, the sensorelement 121 can comprise a plurality of Hall generators which aredisposed at predetermined distances from each other. Based on the Hallvoltages of the individual Hall generator elements, one can ascertan theexact position of the magnet 120.

There is further shown a proportional valve 52 which is utilized toeffect a pressure regulation or pressure adjustment of pressure controlin the hydraulic system.

In FIG. 5, the two proportinal valves 52a, 52b which are shown in FIG. 4cannot be seen as two valves because they are disposed one behind theother.

The adjusting member 102 comprises two plenum chambers 102a and 102bwhich can be put to use in a planned manner in response to a controlledapplication of pressure which causes the piston 105 of the adjustingmember 102 to be acted upon in the axial direction to thus initiate amovement of the central shifting shaft 60.

The adjusting member can constitute a differential cylinder whichcontains a piston having differently dimensioned sides and serving toseparate the plenum chambers 102a and 102b from each other. Thedifferential cylinder is designed in such a way that the pistons orpiston sides which are movable in the two plenum chambers have differenteffective surfaces so that, if the pressure in the two plenum chabers isthe same, the surfaces of the piston or pistons are subjected to theaction of different forces.

The differential cylinder can be designed in such a way that a discretepiston in movably mounted in each of two plenum chambers which areseparated from each other and, for example, these two pistons arecoupled to each other by a connection, such as a piston rod. Theattachment of the element 101 can be affected by means of such a pistonrod, and the point of connection can be disposed axially between theplenum chambers 102a, 102b.

By accurately selecting the relationship of the sizes of the pistonsurfaces relative to each other or by modulating the supply pressureand, if necessary, by resorting to additional energy storing means, suchas springs in the adjusting cylinder, it is possible to modulate theactuating force and to conform it to the mechanical conditions. It is ofadvantage to resort to a system-dependent end position damping duringinitiation of operation of the actuating arrangements because thedifferential force decreases if the hydraulic force remains unchangedand the spring force increases to thus arrive at a condition ofequilibrium between the hydraulic compression force and a mechanicalcounterforce. The result is the same as in the case of end positiondamping.

In due time, the piston is being acted upon with a constant pressurewhich is controlled by a pressure regulating valve so that the pistonperforms a movement in a direction to the right or to the left. At suchtime, the piston moves against the resistance of an increasing forcegenerated by springs which are installed in the interior of thetransmission. Consequently, the piston moves with a constantpressure-generated force against a rising characteristic curve ofsprings. The difference between such forces decreases and the forcesreach a state of equilibrium, i.e., this principle is effective just asan end position damping.

This renders it possible to resort to a simpler regulating algorithmwhich, in turn, renders it possible to increase the velocity of thesystem.

FIG. 6 illustrates a modification of the arrangement of FIG. 5, therebeing retained the central shifting shaft 60, the shaft 66 of theactuator and the mobile connection by means of the pin 64 as well as theadjusting element 102 with the piston 105 and the connection by means ofthe guide sleeve 101 and the extension 107 which latter terminates in aspherical head within the guide sleeve, a spherical joint being providedbetween the guide sleeve 101 and the extension 107. There is also shownthe connecting plate 100 with the bores 50 for attachment of theapparatus. A further difference between the arrangement of FIG. 6 andthe arrangement of FIG. 5 is that the sensor 150 for monitoring of theposition of the axial shifting shaft is located closer to the axis ofthe shifting shaft to thus facilitate a more direct monitoring of theposition of the central shifting shaft because the influence of play andinaccuracies and wear is less pronounced. Furthermore, the sensorconsists of a plurality of Hall generators 151 and a magnet 152 providedon a holder which is borne by the shaft 66.

FIG. 7 is a sectional view of an actuating arrangement, the upper partof FIG. 4 being shown in section as seen from the rear side thereof.There are shown in FIG. 7 the central shifting shaft 60 of thetransmission 4, the shaft 66 with its receptacle 66a for the actuator,as well as an adjusting member 200 with a piston 201. Axial shifting ofthe piston 201 due to the pressurization of the plenum chambers 202 and203 entails an axial displacement of the central shifting shaft 60.

FIG. 7 further shows the spherical joint type connection 210 between theshaft 106 of the adjusting member 102 and the shaft 66, this connectioncomprising a pivotably mounted guide sleeve 101, a spherical head 211and a guide 212 for the spherical head 212. The spherical head isconnected with the shaft 66 by way of an extension 107.

The spherical head, which is provided on the shaft 66 by way of theextension 106, is guided in a socket of the element 212 so that, whenthe central shifting shaft 60 is rotated about the axis 220, the element212 is shiftably mounted in the sleeve 101. Furthermore, a diaphragmspring 221 is disposed between the sleeve and the upper end 212a of theelement 212. This energy storing element 221 can also be present inanother resilient form. There is further shown in this Figure a sensor121 with plug 122 and the arrangement of Hall generators 151 as well asthe magnet 151. Valves, such as relay valves 300, are disposed in theupper right-hand region.

The shaft 66 of the actuator extends into the space 202 and is sealed bya seal, such as an annular seal 301.

FIG. 8 illustrates a further embodiment which corresponds to that ofFIG. 7 but wherein the sensor 121 is disposed in a different region. Themagnet is provided directly on the receptacle 66a of the shaft 66, andthe receptacle 66a accommodates the end portion of the central shiftingshaft 60 of the transmission 4. The axial shifting and/or rotation ofthe central shifting shaft about its axis 220 thus effects a shifting ofthe magnet or magnets to a different position which is determined bymeans of the Hall effect generators 151. In lieu of the magnet, one canalso employ a different transmitter.

The adjusting member 102 of FIGS. 5 to 8 constitutes the selectingcylinder because, due to initiation of movement of the piston 105, thecentral shifting shaft is actuated in a gear selecting direction, Thus,the adjusting member 200 of FIGS. 5 to 8 and its piston 201 constitutethe shifting cylinder because, by selecting the axial position of thepiston 201, the central shifting shaft 60 is caused to move in the gearshifting direction.

In transmissions with an interchange of directions of shifting andselection, there would also develop a corresponding interchange ofactuating directions or actuations.

The pistons 105 and 201 of the adjusting members 102 and 200 constitutedifferential pistons. This means that the area which can be acted uponin the axial direction is greater at one side of the piston than at itsother side. In FIG. 6, the surface 105a is greater than the surface 105bso that, if the pressures applied to the two surfaces are identical,there would develop a resulting force which would cause the piston tomove axially in a direction to the left, as viewed in FIG. 6.Analogously, and as far as the piston 201 is concerned, the surface 201ais larger than the surface 201b so that, again, the application ofpressure to both plenum chambers 202 and 203 of the adjusting memberwould result in the generation of a force which would urge the piston201 axially in a direction to the left.

The arrangement of pistons with side surfaces having areas of differentsizes is shown solely as an example.

In transmissions with an interruption of pulling force, differentmechanisms can be realized for the shifting into and for the selectionof the transmission ratio. Heretofore, the above described embodimentwas that of a transmission wherein a central shifting shaft is movedaxially or the shifting shaft is moved in a circumferential direction.The adjusting members with the cylinder-piston units are distributed andcoupled with the central shifting shaft accordingly.

There are further known transmissions with two rotary shafts, one shaftfor shifting and one shaft for selecting. As concerns the selectingcylinder, such shafts are coupled in a manner as described hereinbefore.

There are also known transmissions which are provided with axiallymovable shifting rods in order to select or to shift into various gearsin the individual shifting paths. Such shifting rods can be actuated byresorting to the aforedescribed adjusting means, such as explained forexample in connection for the shifting cylinder.

FIG. 9 shows a further embodiment of a shifting cylinder 400 which isequipped with a piston having essentially identical surfaces. There isfurther shown the shaft 400 with a receptacle 401 for the centralshifting shaft. At the other end 402 of the shaft 400, there is provideda guide sleeve 403 which receives a spherical head 404, the latter beingconnected with the shaft 405 of the selecting cylinder. Furthermore,there is provided a sensor unit 406 with Hall generators 407 and amagnet 408.

FIG. 10 shows an arrangement including a selecting cylinder 450 with apiston having surfaces of essentially identical size, the plenumchambers 451 and 452 being provided in the end portions of the housing.The plenum chambers 451,452 are bounded by the axially movable pistons454 and 455. The pistons 454 and 455 are coupled or connected to eachother by a connecting rod such as a piston rod. This piston rod islinked to the central shifting shaft by way of a spherical joint or auniversal joint. The spherical head 456 of the spherical joint is movedaxially in response to axial displacement of the connecting rod 453between the pistons 454 and 455 with the result that the guide sleeve457 is pivoted. This causes the central shifting shaft 458 to also turnabout its axis.

FIG. 11 illustrates an array of sensors, such as for example Hallgenerators, 500a to 500d on a carrier such as is shown at 410 in FIG. 9.For example, the carrier 501 can constitute a plastic or metallic partwhich can be inserted into an opening of the actuator housing so thatthe introduction of the conductors can be carried out from the outside.Such a sensor arrangement can be very readily inserted and secured, itbeing possible to provide a threaded, riveted or plug-in connectionwhich results in an inexpensive realization of a local resolutionsensor. The squares 502a to 502g denote the positions which can be takenup by a transmitter, such as magnets, beneath 'the array of Hallgenerators, the gear positions 1, 3 and 5 as well as the reverse gearbeing disposed in the front end portions of the shifting paths, and thegears 2, 4 and 6 being disposed in the rear end portions. The shiftingscheme corresponds to a double-H arrangement of the type shown in asimplified manner in FIG. 12. The vertical lines between the gearpositions denote the shifting paths, such as for example the line 550,and the horizontally extending lines 551 are indicative of a gearselecting movement.

A gear position recognition with assistance from the transmitterarrangement, such as an array of Hall generators, can be carried out,with assistance from the electronic control unit, in such a way that oneevaluates the Hall generator signals of the individual sensors 500a to500d, it being possible to employ Hall generators which exhibit adefinite spatial sensitivity range as indicated, for example, bycircular broken lines 503 surrounding the Hall generators. These spatialsensitivity ranges indicate that a sensor generates a signal, such as aHall voltage, only when the magnet is disposed within such sensitivityrange beneath the sensor. This means that, when for example the sensorat the position 502g is disposed in accordance with a reverse gear,basically only the sensor 500c generates a signal which, basically,departs from zero, and the sensors 500a, 500b and 500d respectivelygenerate signals which do not depart from zero or, at the least, areweak. Analogously, when the transmission is shifted into the first gear,as at 502a, the sensor 500c as well as the sensor 500b generate signalsbut the two other sensors 500a and 500d basically generate no signals,and so forth, up to the gear position 6 corresponding to 502f in whichonly the sensor 500a generates a signal.

By appropriate distribution of Hall generators, such as shown in FIG. 11which illustrates a square array of Hall generators, one can monitor atwo-dimensional field by resorting to essentially unidimensional sensorsin a twodimensional distribution. Depending upon the structuralcharacteristics of the component part which is to be monitored, it canbe of advantage for example if the Hall generators are reduced to aminimum and are secured to the carrier element for example in atriangular or rectangular or square formation.

If the arrangement comprises a single sensor, the latter cannotascertain for example whether the transmitter is located to the right orto the left of the receiver. Basically, such sensor merely detects thedistance. For this reason, such a sensor monitors a "unidimensionalvalue". The cooperation of a plurality of such sensors and theadvantageous evaluation of sensor signals render it possible to achievea two- or threedimensional resolution.

Consequently, the control unit must detect and sample the signals fromthe individual Hall generators in order to ascertain, for example, theposition of the central shifting shaft or, and as shown in theaforedescribed Figures, the control circuit can also serve to ascertainthe position or positions occupied by the shafts of the adjustingmembers, such as adjusting cylinders. As concerns the shaft of theshifting cylinder, it is basically of interest to ascertain, among otherthings, whether the shaft is located in one of the two end positions,and in which end position, as well as whether the shaft is located inthe central neutral position. For example, one can employ two sensorswhich are installed between the central position and the respective endpositions in order to unequivocally ascertain the position of the shaft.In one of the end positions, only one Hall generator having acorresponding sensitivity range is called upon to generate a Hallsignal, the other Hall generator serving to generate a Hall signal inthe other end position, and both sensors generating Hall signals in thecentrally located neutral position.

A corresponding procedure can also be carried out to monitor theposition of the selector shaft, an array of 3 or 4 Hall generators beingof advantage in connection with a shifting scheme with four shiftingpaths as shown in FIG. 12.

FIG. 13 illustrates a hydraulic layout for automated actuation of theclutch 3 and for the selection of gears as well as for shifting of thetransmission 4. Starting from a common pumping unit 600 with an electricmotor 601 as well as with a pumping device 602 which is driven by theelectric motor, a conduit 603 supplies pressurized fluid to anaccumulator 604. The accumulator 604 is connected with apressure-responsive switch 605a which starts the motor unit and hencethe pump when the pressure drops below a preselectable threshold valueuntil the pressure in the accumulator 604 rises above a secondpreselectable threshold value at which the switch 605a again turns offthe motor unit 601. The accumulator 604 and a hydraulic conduit 605 arefollowed by conduits 606 and 607 for two proportional valves such aspressure feedback proportional valves 608 and 609. As shown in FIG. 13by two broken lines, the hydraulic scheme or hydraulic layout of FIG. 13is divided basically into three sections.

A first section A contains the hydraulics for actuation of the automatedclutch, a section B contains the hydraulics for the initiation of thegear selecting operation, and the section C contains the hydraulics for20 the initiation of the gear shifting operation. Starting with apressure P_(v), which prevails in the conduits 607 and 606, the pressurein the conduit 610 and in the conduit 611 is controlled or regulated bythe pressure feedback proportional valve.

If the transmission is an automated shift transmission, the actuation ofthe clutch and the initiation of the shifting and selecting operationsnormally take place in a basically fixed sequence. Prior to a shiftingor selecting operation, the clutch must be disengaged at least to suchan extent that it is possible to shift out of a gear. Thus, as a rule,the first actuating operation involves a disengagement of the clutch.The second actuating operation can be said to constitute a shifting outof a particular gear, thereafter a selecting operation can entail achange of path but this is optional, and the clutch is thereafterreengaged or is actuated in a planned manner in such a way that it isset for the transmission of a transmissible torque.

In accordance with the aforementioned sequence, the clutch is actuatedin a first step, the pressure feedback proportional valve 608 is used toset the pressure P_(K) in the region 610 in such a way that the pressurein the plenum chamber 613 of the disengaging member is selected in aplanned fashion. Depending upon the area A_(K) of the side 614 of thepiston 615, and upon the selected pressure, the disengaging bearing 616is acted upon with a corresponding force P_(K) *A_(K) in the directionof disengagement. The force F which is required by the actuator is shownin the diagram 620 as a function of the extent of clutch disengagingmovement S.

Thus, the valve 608 must be regulated in such a way that pressure P_(K)in the region 610 and/or 613 can be varied in a planned manner so that,and depending upon the command from the control unit, the clutch isengaged or disengaged or is maintained in a predetermined condition ofengagement.

When, in the course of a shifting operation, the clutch reaches acondition of engagement in which it is at least possible to shift out ofa gear, the valve 609 is caused to regulate the pressure P_(S) in theregion of the conduits 630, 631. The same as the valve 608, the valve609 can also constitute a pressure feedback proportional valve, thearrangement of these two valves 608 and 609 corresponding to that of thevalves denoted in FIG. 4 by the reference characters 52a and 52b.

The hydraulic circuit which is shown in the section C of FIG. 13 andserves to shift comprises the aforementioned 20 pressure feedbackproportional valve 609, a relay valve 632 as well as a conduit 633 and adifferential cylinder 635.

The mode of operation of this section or region C will be described ingreater detail with reference to FIGS. 14 and 15. There further takesplace a monitoring of the distance s and/or of the position of thepiston 635 in the differential cylinder, for example, by resorting to asensor.

The utilization of differential cylinders, such as pressure differentialpiston systems, exhibits the additional advantage that only one shaftseal is necessary.

The differential cylinders are preferably controlled by means of aproportional pressure regulating valve which serves to modulate theactuating pressure. This can also be replaced with a supply pressurewhich is regulated by a pressure limiting valve.

In FIG. 14, the relay valve 632 is set in such a way that the conduit633 is connected with the oil sump 670, i.e., the pressure in theconduit 633 is practically zero. If the proportional valve 609 in theconduit 630 is set to select a pressure P_(S) which departs from zero, asubstantially identical pressure is set up in the plenum chamber 650and, due to the action of pressure upon the surface 651, A₂, the forceacts upon the piston 635 in an axial direction to the left. This causesthe piston rod 652 to move in the axial direction which, for example,can result in an axial movement of the gear shifting shaft. The pressurein the chamber 654 is nil and the action of force upon the surface 655,A₁ is basically zero. In this manner, one can initiate for example ashifting operation from the neutral position N into the region H, namelyinto a rear region of the shifting paths or from a region V, namely thefront region of the shifting paths, into the neutral region N.

FIG. 15 illustrates an embodiment in which the relay valve 632 is set insuch a way that the conduit 631 is communicatively connected with theconduit 633. If the proportional valve 609 is caused to raise thepressure in the conduits 630 and 633, the differential cylinder isactuated in the following way: The pressure in the plenum chamber 650 isthe same as in the plenum chamber 654, namely the magnitude of the forceF acting upon the surface A₂, 651 equals P_(s) *A₂, the force actingupon the surface 655, A₁ being equal to P_(s) *A₁ =F₁ and, since A₁ >A₂,the piston is being acted upon axially in a direction to the right witha differential force (F₁ -F₂).

If the ratio of the areas of the surfaces A₁ and A₂, namely 651 and 652,is such that the area of the surface A₁ is twice that of the surface A₂,the magnitude of the force acting upon the piston of FIG. 14 is the sameas that of the force acting upon the piston in FIG. 15, the onlydifference being the direction of the action of force. In FIG. 14, thepiston is being acted upon in a direction toward H whereas, in FIG. 15,the piston is being acted upon in a direction toward V.

By measuring the movement which is indicated by the symbol s at thepiston 635, one can regulate or control, such as for example regulate orcontrol as a function of the extent of movement, the movement and/or theposition of the piston 635 and hence the extent of movement of internalshifting elements in the transmission 4 in the direction of shiftingmovement along the shifting paths. In the course of synchronization ofthe gear which is to be shifted into, it can happen however that theextent of movement is zero and that it becomes necessary to control orregulate the action of pressure or the action of force; under suchcircumstanes, it is possible to carry out a regulation of pressureduring the synchronizing stage by means of the pressure feedbackproportional valve 609.

The realization of the pressure- or force regulation or control duringshifting and/or during selection of the transmission ratio constitutes amain advantage of the invention over mere movement regulations ormovement controls. A movement regulation or control can be superimposedupon a pressure- or force regulation.

An advantage of the pressure- or force regulation or control is that onecan select a planned force or pressure which conforms to the operatingpoint. For example, the synchronizing operation can be carried out witha preselectable force in order to protect the synchronizing means of thetransmission. It is equally possible to control or regulate the force orthe pressure in dependency upon the driver.

A corresponding pressure regulation or pressure control duringsynchronizing corresponds to a force regulation or force control duringgear synchronization, and a comfortable shifting can be carried out orinitiated in that the force is small during synchronizing but the forceis large during synchronizing in the case of a sporty shifting. Thus, inorder to carry out a gear shift, in addition to the differential pistonaccording to FIGS. 13 to 15, it is merely necessary to employ a relayvalve which is installed downstream of a proportional valve, andpressure feedback proportional valve, such as for example a pressurereducing valve. For example, the relay valves can constitute 3/2-wayspherical seat valves. As disclosed, a pressure regulation can besuperimposed upon a movement control or movement regulation in thecourse of a synchronizing operation.

In this connection, FIG. 13 illustrates a force-time relationship in acoordinate system which is denoted by the character 660. If theactuation of the valves 609 and 632 entails a positioning of the centralshifting shaft in the neutral region, as seen in the direction ofshifting, the hydraulic unit in the region B of FIG. 3 can carry out achange of paths, namely a gear selecting operation. In order to carryout such a gear selecting operation, a differential cylinder 700 isactuated by means of two valves 701 and 702 in such a way that the axialmovement of the component part 703 which is connected with the piston706 renders it possible to move the selecting shaft. The symbol sdenotes, in the same manner as in connection with the coupling cylinderand the shifting cylinder, that one can carry out or that one carriesout a measurement of the distance in order to effect a regulation orcontrolling of the covered distance.

A pressure regulation or control can be superimposed upon the movementregulation or control.

FIG. 16 shows a force-distance progress or a force-angle relationship inthe course of a gear selecting operation within the transmission. Inconventional transmissions, the central shifting shaft is acted upon bya force which is supplied, for example, by springs so that, without theneed for the application of an external force, the central shaft isurged to path/position 3/4 in the neutral path. This means that, in thepath/position 3/4, the central shifting shaft is being acted upon by asmallest force and that an increasing force prevents an automatic changeof paths during a change into the path 1/2 or 5/6 or R. An increasedforce is also required during a transition into the path of the reversegear R.

If one is to identify the forces which are required to change paths, themaximum force P_(W) *A₁ can be associated with the path change from thepath 3/4 into the reverse gear R, and the change from the path 3/4 intothe path 5/6 requires a force P_(W) *A₂ in the opposite direction. Achange from the path 3/4 into the path 1/2 is selected in such a waythat it requires a force P_(W) *(A₁ -A₂).

It is now assumed that the surfaces A₁ and A₂ are the surfaces of adifferential cylinder and that the ratio of their areas is 2:1, i.e.,the area of the surface A₁ is twice that of the surface A₂. It followsthat if the pressure in the first plenum chamber 705 with surface A₁ israised and the pressure in the second plenum chamber 704 with surface A₂is relieved, the piston is acted upon with a resultant force whichequals P_(W) *A₁. If only the second plenum chamber 704 with the surfaceA₂ is subjected to a pressure P_(W) and the pressure in the first plenumchamber 705 is relieved, the resultant force P_(W) *A₂ acts upon thepiston in the opposite direction. However, if the fluid in the first andsecond plenum chambers 705, 704 is subjected to the pressure P_(W),there again results a force acting in the opposite direction and havinga magnitude P_(W) *(A₁ -A₂) so that the piston of the differentialcylinder can be acted upon in two directions with identical forces andin one direction with doubled force, and all this necessitates theutilization of only two relay valves.

Thus, the magnitude of the selected pressure P_(W) depends upon whichforces prevailing in the interior or externally of the transmission actupon the central shifting shaft during selection of a gear. Inaccordance with an advantageous design of the differential piston withthe surface ratio 2:1, there are established the desirable circumstancesthat the two forces for the selection from the path 3/4 into the path5/1 or from the path 3/4 into the 1/2 have identical magnitudes and thetransition from the path 3/4 into the path R is twice as large as theforces which must be applied in order to effect a change into the othertwo paths.

The FIGS. 17 to 20 illustrate these facts on the basis of partialdiagrams. In FIG. 17, the valves 701 and 702 are set to relieve thepressure in the plenum chambers 704 and 705. Therefore, the pistonremains in the illustrated position, which can be called an idleposition because the detent force of the transmission must be exceededduring a change of gear so that the selector shaft remains in theneutral path and assumes the position 3/4.

In FIG. 18, a pressure P_(W) is established in both supply conduits 612aand 612b, and the valve 701 is set to subject the fluid in the plenumchamber 704 to a pressure P_(W) while the valve 702 relieves thepressure in the plenum chamber 705. Consequently, the surface A₂ isbeing acted upon by an axially oriented force in a direction to theright so that there can take place a change of paths, for example, fromthe 3/4 path to a 5/6 path.

In FIG. 19, a pressure P_(W) is set up in the hydraulic conduits 612aand 612b, the valve 701 and the valve 702 being adjusted for throughflowso that the pressure P_(W) is the same in the plenum chambers 705 and704. Due to the surface area diference (A₁ -A₂)=A₂, a force A₂ can act,for example, in the axial direction toward the left, upon the piston andhence upon the the cylinder. Strictly speaking, the effective forceP_(W) *(A₁ -A₂), and the selection of A₁ and A₂ is preferably caused toconform to the design of the transmission.

Next, FIG. 20 shows the application of pressure P_(W) in the chamber 705because the valve 701 is set to relieve or reduce the pressure in thechamber 704 and the valve 702 is set to raise the pressure in thechamber 705. Consequently, the piston is acted upon in the axialdirection to the left by a maximum force P_(W) * A₁. This is the forcewhich is necessary to shift into the path R as shown in FIG. 16. Therelationships of the forces can change if the conditions in thetransmission are different so that, for example, the path 1/2 isdesigned as the path with the application of minimal force and a muchgreater or somewhat greater force is required for a gear change from thepath 1/2 into another path.

In accordance with the method which was explained with reference toFIGS. 17 to 20 and which is resorted to in order to actuate theselecting cylinder 700, completed selection of the path is followed bycompletion of the shifting operation in such a way that, once in theshifted in or selected path, the central shifting shaft is caused tomove in the forward or rearward direction V, H so that the transmissionis shifted into gear. In the next step, the clutch can be actuated againin a direction toward closing, i.e., the clutch is reengaged.

The pressure modulation for the purpose of initiating the gear selectingoperation is carried out with the pressure feedback proportional valve608 and, during each stage of the gear selecting operation, the pressureP_(K) must be so high that the clutch, to which the pressure P_(K) isbeing simultaneusly applied in a direction toward opening, remainsdisengaged.

In accordance with the invention, the two pressure feedback proportionalvalves 608 and 609 of FIG. 13 are designed in such a manner that theclutching and gear selecting operations are initiated by the valve 608but the operation of shifting into gear is initiated by the other valve609 because the clutching and selection necessarily follow each other,i.e., must or should be carried out serially but the shifting operationcan be initiated even though the clutch is not as yet completelydisengaged, i.e., a second valve 609 is needed for the carrying out ofthe shifting operation.

In accordance with a further advantageous possibility, provision can bemade that the initiation of the gear shifting operation also beginsubsequent to completion of the clutching operation so that theinitiation of the gear shifting operation can also be controlled by theproportional valve 608. In this manner, one can ensure that only asingle proportional valve is needed to initiate sequentially theclutching operation, the shifting operation and the selecting operationand, furthermore, that additional regulation merely involves that ofrelay valves. A sequence could be selected as follows: disengaging theclutch, shifting from a gear position into neutral, selection (optional)and again shifting into a gear prior to subsequent engagement of theclutch. This cycle can be stored sequentially in the control apparatusso that there can take place an automated carrying out of operating theshift transmission and the actuation of the differential piston systemdoes not necessitate a serial selection of gear stages. For example, byskilled selection of the paths, one can shift from the first gear intoany desired gear.

The relay valves 701, 702, 632 are so-called black-white-shiftingvalves, and the proportional valves can be set to assume any desiredcondition. As a rule, the volumetric flow to actuate the clutchdisengaging member, such as a central disengaging member, is in therange of 1 to 10 liters per minute and the initiation of actuation ofthe gear selecting operation necessitates values in the range of 0.1 to5 liters per minute, preferably between 0.3 and 1 liter. Correspondingapplies for the initiation of the gear shifting operation. The pump 602which is shown in FIG. 13 can constitute, for example, a radial pistonpump.

FIG. 21a illustrates an actuator 13, such as the actuating unit of FIG.3, in an elevational view, there being shown the hydraulic conduits andthe valves which are installed in the actor. The relay valves S1, S2 andS3 correspond, in the hydraulic scheme, to the valves 701, 702 and 632,i.e., the valves S1 and S2 control the differential cylinder 700 for thecontrol of the selecting operation, and the relay valve S3 controls theshifting operation.

There is further shown a proportional valve 609. In this Figure, theproportional valve 608 for the control of clutch actuation and of thegear selecting operation is located behind the valve 609 so that it isconcealed by the latter.

The hydraulic conduit L1, 605 establishes a connection from theaccumulator 604, i.e., from the pump 600, and this conduit L1establishes a connection between the two proportional valves 608 and 609on the one hand, and the hydraulic supply system on the other hand. Thehydraulic conduit L2, 612 connects the proportional valve 608 with therelay valves 701, S1 and 702, S2. The hydraulic conduit L3 connects therelay valve S1, 701 with the differential cylinder 700, and thehydraulic conduit L4 connects the relay valve F2, 702 with thedifferential cylinder 700. The hydraulic conduit L7 connects the relayvalve S3, 632 with the differential cylinder 635 for switching, and thehydraulic conduit L6, 630 connects the proportional valve 609 with thedifferential cylinder 650 for switching.

FIG. 21b again shows the actuator but in a different view, there beingshown the hydraulic conduits L6 and L7 for actuation of the differentialcylinder 635 for switching by way of the relay valve S3, 632 andproportional valve 609.

FIG. 21c illustrates the actuator in a further view, there being shownthe conduit L2 and the conduit L1. There are further shown theproportional valve 609 and the proportional valve 608.

Furthermore, it can be seen that the sensor piston 900, which is shownschematically in FIG. 23, is built into the actuator. Thus, the sensorpiston is integrated into the conduit 610 in the hydraulic plan on page13. The outlet of the sensor piston 900 is a connection for the conduitL₅ to the central disengaging member ZA for the clutch.

The control apparatus is shown in greater detail in FIG. 22, the controlapparatus 800 being illustrated as being framed by a broken line. Thecontrol unit 800 comprises a source 801 of potential which supplies thesensors and the units of the control unit. It is also possible toprovide a sensor interface 802 which processes the digital signals.There is further provided a sensor interface 803 for analog signals, aswell as a CAN-bus interface 804. For example, the inputs of the sensorinterfaces (digital) 802 are the selection- and shifting inputs as wellas the pressure switch of the accumulator. For example, the inputs ofthe sensor interfaces (analog) 803 are the path recognition or theshifting movement monitoring as well as the monitoring of the clutchmovement.

The arrows which are shown in FIG. 22 denote the signal transmitting andsupply connections.

For example, the CAN-bus interface 804 receives input signals from thegas pedal or gas pedal sensor as well as signals denoting the rotationalspeed of the engine, the RPM of the wheels, the engine torque, the angleof the throttle valve, the brakes such as operational and parking brakesas well as for example the idling switch and optionally whether or notantislip regulator is active, as well as other possible signals. TheCAN-bus can receive signals by way of the outputs of the interfacecomponents, such as for example an indication of the gear ratio, anindication of the condition of the clutch, an engine input, a starterrelay or a tempomat. Still further, the unit 800 encompasses a centralcomputer unit 805, such as a microcontroller, which carries out thecomputing operations for the control or regulation, it being possible toprovide a flash EPROM.

There are further available diagnosis-interface modules 806, forexample, to furnish during the prototype stage signals denoting theoperating conditions. Furthermore, it is possible to provide aniso-interface 806a for the purposes of diagnosis. It is also possible toaddress the diagnosis-interfaces 806, 806a during the service intervals.Still further, there is provided an output driver 807 for the relayvalves and an output driver 808 for the proportional valves; thesedrivers control the valves and, at the same time, can receive signalsfrom the valves, such as position indicating signals.

Further control units, such as controls for the engine, the hydraulicpump, are not illustrated. The same holds true for the sensors, such asHall generators, for the detection of the selection- and shifting inputsor the recognition of the gear ratio or the recognition of the shiftingpath. Such signals are transmitted to the control unit as indicated bythe arrows (denoting signal transmitting conductors).

FIG. 23 illustrates a sensor piston- or floating piston arangement 900with a floating piston 901 which is being acted upon by springs 902 and903 within a chamber. The two springs fix the piston in the position"clutch engaged". The springs are preferably designed in such a way thatthey can barely overcome the frictional forces acting upon the piston,i.e., that they can move the piston in the cylinder when the movement isnot prevented by hydraulic means. There are further provided hydraulicconduits 904 and 905 one of which connects the proportional valve 906with the chamber 907 and the other of which connects the chamber 908with the plenum chamber 909 of the central disengaging member 910 whichlatter actuates the clutch by way of a disengaging bearing 911 as wellas by means of the diaphragm spring 912 only certain portions of whichare actually shown. Furthermore, the arrangement 900 is provided with asnifting opening, such as a snifting bore 913, which is connected withthe sump 915 by way of a hydraulic conduit 914. When a control edge 916advances beyond the snifting bore, this ensures the establishment of apressure equilibrium between the bodies of fluid in the cylinderchambers 907 and 908. This takes place only when the clutch is fullyengaged, namely the snifting bore can be exposed only in such conditionof the clutch.

In order to monitor the axial position of the piston 901, there isprovided a position sensor 917 which monitors the position of the pistonin a contactless fashion by means of at least one transmitter, such as amagnet 918. In the embodiment of FIG. 23, the position monitoring sensoris a Hall effect generator which cooperates with a, for example,ring-shaped magnet 918. The ring magnet 918 can be disposed at a desiredportion of the piston, for example, as shown in FIG. 23; however, thering magnet can also be installed at an end region of the piston.

When the clutch is engaged, the diaphragm spring 912 of the clutch actsupon the hydraulic system in such a way that the piston is fixedbasically in the position "clutch engaged". During disengagement of theclutch, the piston is displaced through a certain distance dependingupon the volume of oil and the diameter. Together with the hydraulictransmission, this distance is proportional to the clutch movement.Thus, the position of the piston 901 is characteristic of the extent ofengagement of the clutch so that one can ascertain the torque which canbe transmitted by the clutch on the basis of the position of the piston.

In addition to the aforementioned Hall generators, the sensors canpreferably constitute also other types of sensors with local resolutioncharacter, such as for example, an inductive sensor wherein an inductioncoil is employed to monitor the extent of penetration into the windingof a ferromagnetic material which is connected with or is provided onthe piston.

If the piston exhibits a leak, namely if its function is improper, forexample because the hydraulic medium flows from the chamber 907 into thechamber 908, the piston 901 moves relative to the housing 920 while thecondition of engagement of the clutch remains unchanged. When the clutchis disengaged, the movement of the piston is such that it graduallymoves toward the "engaged position". This is attributable to the actionof the springs 903 and 902. If the clutch is thereupon engaged, thepiston migrates beyond the position which appeared to be the "engagedposition" since it has assumed such position already at a time when theclutch was still disengaged. However, the piston migrates only to anextent such that the snifling bore establishes an equalization ofvolumes. The positional equalization, namely the shifting of the pistonback to the position which is considered to be the "engaged position",is assisted by the springs. In this manner, one can ensure a possiblylimited determination of clutch movement even in the event of improperoperation such as a leakage at the sensor piston. The provision of asnifling bore 913 is intended to compensate for faulty operation, suchas for example thermal effects. This snifling bore is provided in theregion of an end position of the piston and is exposed at certain timeintervals. The control unit selects the intervals for the exposure ofthe snifling bore at such operating points at which this exposurepresents no problems as concerns the operational reliability of theclutch. An exposure of the snifling bore takes place as a result ofcomplete engagement of the clutch. This initiates an operation similarto a "hydraulic reset", the quantities of oil in the chambers 907, 908are equalized and the system is back in the original state, namely astate which is assumed in the absence of a leakage or other faultyoperation.

A system employing the sensor piston or floating piston of FIG. 23 canbe put to use not only to separate the media at the transmitter andreceiver sides but also exclusively as a measuring system without amedia separating effect. In the event of a media separation, thepressure medium, such as a fluid, which is utilized at one side of thepiston can be different from that at the other side of the piston. Forexample, one can employ a braking fluid and a hydraulic fluid ATF.

FIG. 24 illustrates diagrammatically the progress of an automatedclutching, shifting and selecting operation as a function of time, i.e.,the velocities of the pistons of the adjusting members or of the shaftsof the adjusting means are measured along the ordinate. The curve 1000denotes the velocity of the master cylinder piston during clutching, thecurve 1001 denotes the velocity of the adjusting member for shifting,and the curve 1002 denotes the velocity of the adjusting member for gearselection, all as a function of time.

The clutch is disengaged at the instant t=0.1003, i.e., the velocity ofthe clutch actorics increases. Prior to complete disengagement of theclutch at the instant 1004, the gear shifting operation is alreadyinitiated, as at 1005. The gear selecting operation is initiated at theinstant 1006 and is completed at the instant 1007. In the course of thegear selecting operation, the velocity of the monitored element of theshifting actorics did not decrease to zero, i.e., during this stage ofgear shifting one takes advantage of the so-called tiltable shiftabilityof the transmission. This means that it is possible to carry out achange of paths at a position within a shifting path before the shiftingactorics reach the neutral position, such as the neutral path.

The reaching of the shifting velocity 1001 at the instant 1008 is theresult of synchronization in the newly selected gear, and the shiftingoperation is completed at the instant 1011. The clutch is reengagedbetween the instants 1009 and 1010. A reduction of the velocity of theshifting actor at the instant 1008 entails that, during this stage ofmovement control or movement regulation, one can or one must carry out aslave pressure regulation of pressure control because, if the velocityis zero, the control- or regulating value disappears if only a movementregulation or movement control is being carried out.

FIG. 25 is a schematic partial sectional view of a transmission bellwith a flywheel 1101, a clutch disc 1102, a pressure plate 1103 as wellas a diaphragm spring 1104 and a disengaging bearing 1105. Suchcomponent parts of the clutch are coaxial with the transmission inputshaft 1106, and this clutch determines the magnitude of transmissibletorque. The disengaging position of the disengaging bearing 1105 ismonitored by a sensor 1107 which extends into the interior of thetransmission bell through an opening in the transmission bell. Theholding means 1108 for the sensor 1107 is screwed onto or plugged intothe transmission bell from the outside.

FIG. 26 is an enlarged view of a sensor. A flexible stress bar 1200 issecured to the transmission bell by way of a sensor plate 1201 and, dueto axial movability of the disengaging bearing 1105, there takes place abending of the stress bar 1200, and such bending is monitored by asensor 1202. For example, this sensor can constitute a strain gauge or apiezoelectric crystal. Thus, the sensor consists essentally of abendable rod which is fixedly anchored at one end and the other end ofwhich is deflectable at right angles to the longitudinal direction ofthe bar. Due to such bending, the marginal fibers or marginal zonesundergo stretching and compression which is detected by resorting to asuitable monitoring principle (strain gauge, piezo, etc.). The processedoutput signals, which are transmitted to the central control unit by wayof a connecting cable 1203, are a direct indication of the extent ofbending or actuating movement if the resolution and the accuracy ofreproduction are acceptable. It is advisable to locate the sensorelements close to the locus of anchoring of the stress bar. This ensuresthat the critical parts are not located in the region of elevatedtemperatures. Another advantage is that the sensor can be integratedinto the threadedly connectable plate 1201 and the maximum stretching ofthe stress bar is in this region.

The clutch movement sensor which is illustrated in FIGS. 25 and 26monitors the axial displacement of the disengaging bearing without theneed for the provision of additional moving parts. Moreover, thetemperature-sensitive component parts are disposed outside of the clutchspace or in the marginal region of the clutch space. The sensor is wellsuited for mounting on existing systems, i.e., for the utilization as anadd-on sensor because, save for the small and often existing opening inthe wall of the transmission and the available fastening means, it isnot necessary to carry out any further modifications.

In an automated shift transmission, the shifting rod is to carry out twomovements.

1. a rotary movement for the selection of paths, and

2. a translatory movement during shifting (withdrawing from and shiftinginto a gear)

All presently preferred prerequisites which are required to carry outthe "shifting" operation are described in the following list.

1. Utilization of a differential piston which entails that only oneshaft seal is necessary

2. hydraulic circuitry according to the plan, see for example FIG. 13.

the pressure modulating valve preferably constitutes a proportionalpressure regulating valve for the modulation of shifting pressure. Theshifting pressure determines the synchronizing torque and hence thesynchronizing speed to thus exert a pronounced influence upon theconvenience of shifting. In this plan, there is employed a proportionalpressure reducing valve. However, this could be replaced with a supplypressure regulatable by a relief valve.

The relay valve is utilized for the selection of the direction ofmovement.

The force P_(S) *(A₁ -A₂) acts in a movement direction to the right, andthe force P_(S) *A₂ acts in a direction to the left. If, and as ispreferred, the areas of A₁ and A₂ are the same, there follows anidentical controlled amplification.

If the valves are set to connect with the tank, no forces are actingupon the shifting rod. This is preferably realized in the position"electrical actuator currentless".

The pressure source is a conventional accumulator-charging unit. Itsupplies the system pressure.

The clutching pressure and the shifting pressure are branched off thesystem pressure, and this necessitates large dynamic volumetric flows.This ensures that the mutual influencing, if any, of the valves isminimal because the accumulator furnishes a pronounced damping action.

The supply pressure for selection is branched off the clutchingpressure. Clutching and selection as well as selection and shifting canbe initiated entirely independently of each other.

The clutching pressure, which is also the supply pressure for gearselection, should be substantially constant if, for the purposes ofdynamics, the clutch remains slightly engaged.

If this is not necessary, it is possible to slightly modulate theclutching pressure which serves as supply pressure for gear selection inorder to optimize the selecting operation. However, a prerequisite forthis is that such pressure be higher than the pressure which is requiredfor the disengagement of the clutch. It is of advantage if the clutch isdisengaged by resorting to hydraulic pressure.

In the absence of current (e.g., failure of the electronics), themomentary condition of shifting remains unchanged, i.e., the clutchremains engaged in a particular gear of in neutral.

As far as the clutch is concerned, there exist two possibilities:

1. The clutch is engaged when the pressure reducing valve connects tothe tank in the absence of current flow. This is better, as far as theconsumption of energy is concerned, because no current consumption takesplace when the clutch is engaged.

2. The clutch becomes disengaged when the clutch pressure reducing valveis currentless and shifts the clutch for the application of systempressure.

Such pressure might drop gradually in view of potential leakage to thuseffect a gradual engagement of the clutch. This procedure might bepreferable as far as safety is concerned even though it is lesssatisfactory insofar as the consumption of energy is concerned. However,this enables the clutch to act as a parking brake.

FIG. 27 illustrates a hydraulic plan for initiating the operation of atransmission, such as for example, a transmission which shifts with aninterruption of pulling force, and the operation of a torquetransmitting system, such as a clutch.

Basically, the hydraulic diagram of FIG. 27 is divided into twosections. One of the sections is denoted by the character 1300 andconstitutes a hydraulic supplying unit, and the other section 1301constitutes an actuating unit, such as an actuating unit. The supplyingunit 1300 comprises an electromotor 1302 serving to drive a hydraulicpump 1303. There is further provided a check valve 1304 as well as anaccumulator 1305 for storage of a pressurized pressure medium withinsuch unit. There is also provided a sensor 1306 which ascertains whetherthe hydraulic pressure prevailing in the accumulator is above or below apreselectable threshold value. If the pressure in the accumulator 1305is beneath a first preselectable value, the motor for the pump isstarted until the pump ensures that the pressure in the accumulator hasrisen above a second preselectable value.

Starting from the hydraulic conduit 1307, the adjusting members for theactuation of the torque transmitting system, such as a clutch, or ofactuating units for shifting into and/or for the selection of gears in atransmission are controlled by valves. In the embodiment of FIG. 27,each adjusting member is provided with its own independent supply path,such as a hydraulic path. Proceeding from the conduit 1307, thehydraulic conduit 1308 supplies fluid for actuation of the clutch, thehydraulic conduit 1309 supplies fluid for the gear selecting operation,and the hydraulic conduit 1310 supplies fluid for the gear shiftingoperation.

The proportional valve 1311 can constitute a proportional directionalcontrol valve in order to control or regulate the pressure P_(K) in thehydraulic conduit 1312, namely the pressure which prevails in the plenumchamber 1313 of the hydraulic clutch disengaging member 1314 foractuation of the clutch.

The valve 1311 can constitute a proportional directional control valveor a proportional pressure reducing valve. Analogously, the proportionalvalve 1311 can be provided with an internal pressure regulating circuit(pressure reducing valve). Such proportional valves are proportionalvalves of special design, particularly with an additional internalcontrol loop. In such a pressure feedback pressure regulating valve, theregulated pressure can be the load pressure prevailing in the pressurezone 312. An advantage of this is that the actuating variable can beconstituted by the pressure which is to be controlled or regulated.

The pilot pressure P_(V) in the conduit 1309 is utilized to select, in aplanned manner, the pressure P_(W) for the initiation of the gearselecting operation. The connection 1309 directly from the accumulator1305 or from the pump to the relay valves 1320 and 1321 constitutes anadvantageous modification of the hydraulic circuit which is shown inFIG. 13 because this renders it possible to initiate an independent gearselecting operation and an independent clutching operation without itbeing necessary to influence one of these procedures in dependency uponthe other procedure. The shifting operation as well as the actuation ofthe valves 1320 and 1321 are based on the situations described withreference to FIGS. 17 to 20 so that the description need not be repeatedhere. However, reference should be had to the description of suchFigures.

The pilot pressure P_(V) in the region 1310 is converted by the valve1330 into control pressure P_(S) for initiation of the gear shiftingoperation, the selection of the pressure PS taking place by way of therelay valve 1331 and the proportional valve 1330, such as a proportionaldirectional control valve or a pressure feedback proportional pressurereducing valve. Reference should be had again to the descriptions of thepreceding Figures.

FIG. 28 illustrates a further advantageous embodiment of a hydrauliccircuit having a hydraulic unit with an electric motor 1302 serving todrive a pump 1303, with a check valve 1304, an accumulator 1305 as wellas with a sensor 1306 which monitors the pressure of hydraulic fluid inthe accumulator. Starting at the junction 1390, one employs hydraulicconduits 1308, 1309 and 1310 in order to initiate the control ofpressurized fluid for the clutching operation by way of adjusting member1314, the gear selecting operation by way of adjusting member 1322, aswell as the gear shifting program by way of the control member 1332. Thefluid pressure in the plenum chamber 1313 of the adjusting cylinder isselected by a proportional valve, such as a pressure feedback pressurereducing valve 1311. The fluid pressure in the plenum chambers of theadjusting member 1332 is selected by the proportional valve 1330 andrelay valve 1331.

In order to provide the pressure P_(W) for gear selection, a pressurefeedback proportional valve 1350 furnishes a control pressure which iscontrolled by the valves 1320 and 1321 for the purpose of being appliedin the plenum chambers of the adjusting member 1322.

In the fluid path 1309, the accumulator 1305 can be followed by athrottle valve 1360 or a primary flow restrictor, this throttle valve1360 being installed upstream of the relay valves 1320 and 1321 whichinitiate the gear selecting operation. The throttle valve 1360 effects areduction of the pressure which is being applied to the relay valves1320,1321 as compared with the pressure in the accumulator 1305. If thepilot pressure P_(V) in the accumulator 1305 is sufficiently low, thethrottle valve can be dispensed with. If necessary, a throttle valvecorresponding to the valve 1360 can also be provided in the flow path1308 and/or 1310.

FIG. 29 illustrates an actuating unit 1400, such as an actuating unit,with a first adjusting member 1401 for the carrying out of the shiftingoperation as well as with a second adjusting member 1402 for initiationof the gear selecting operation. The shifting movement as well as theselecting movement, and also the actual condition of the transmissionare monitored by a sensor 1403 which can be secured to the actuatingunit 1400. It is also possible to interchange the functions of theadjusting members 1401 and 1402 in dependency upon the nature of thetransmission which is being utilized or controlled.

The adjusting member 1402 comprises a piston 1410 which is installed ina receptacle and separates two plenum chambers 1412 and 1413 from eachother. Those surfaces of the piston which are being acted upon bypressurized fluid and entail an axial displacement of the pistonconstitute differential surfaces, i.e., the piston is a differentialpiston so that, when the pressures are the same, this results in thedevelopment of different axially oriented forces.

The adjusting member 1402 is constructed in such a way that a firstplenum chamber 1420 confines a piston surface 1421 and that a secondpiston is provided in a second chamber region 1430 within the housingand has a second piston surface. The two pistons are connected to eachother by a piston rod 1422. When the fluid in the plenum chambers 1420is pressurized, there takes place a shifting of the piston rod 1422 andhence a pivoting of the fork 1440 so that the central shifting shaft1441 is rotated. This entails a displacement of the transmitter 1450 forthe sensor 1403 so that the sensor detects a different position.

The actuating unit 1400 is connected with the hydraulic unit by means ofhydraulic supply conduits in such a way that, for example, a secondblock contains the valves which initiate the operation of the actuatingunit, such as an actor unit. Furthermore, a hydraulic pump, too, can beintegrated into such block; however, the pump can also be mountedseparately.

Furthermore, the initiation of operation of the clutch is effected by anadjusting member which preferably acts directly upon the clutch. Due tothis, such adjusting member is not integrated into the actuating unit1400.

The patent claims which are filed with the application are formulationproposals without prejudicing the acquisition of broader patentprotection. The applicants reserve the right to claim additionalfeatures which, up to this time, are disclosed solely in thespecification and/or in the drawings.

The references made in the dependent claims point toward furtherdevelopment of the matter of the main claim with features of therespective dependent claims; they are not to be understood as a waiverof the attempt to obtain independent substantive protection for thefeatures of the referenced dependent claims.

The features recited in such dependent claims constitute independentinventions for constructions not dependent upon those of the matters ofthe preceding dependent claims.

Still further, the invention is not limited to the embodiments which aredisclosed in the specification. On the contrary, it is within thepurview of the invention to carry out numerous changes andmodifications, especially such variations, elements and combinationsand/or materials which, for example, might be of an inventive nature asa result of combination or modification of features and/or elements ormethods outlined in the general description and in the description ofembodiments and in the claims and which, as a result of a combination offeatures, can lead to a new product or to novel method steps and/orprocess steps, also insofar as they pertain to methods of producing,testing and operating.

What is claimed is:
 1. A motor vehicle comprising a prime mover; anautomated transmission shiftable into a selected one of a plurality ofgears; a system for transmitting torque between said prime mover andsaid transmission, said system being operable to assume engaged anddisengaged conditions; a hydraulic unit comprising a source ofpressurized fluid including an accumulator, means for connecting saidsource with said transmission, and regulating means associated with saidconnecting means and operable to effect a planned selection of andshifting into one of said gears; and means for operating said system andfor operating said regulating means, wherein said operating meanscomprises at least one proportional valve and a conduit connecting saidproportional valve with said system and said regulating means comprisesat least one selector valve provided in said connecting means downstreamof said proportional valve as considered in the direction of fluid flowfrom said source to said transmission, said at least one proportionalvalve being arranged to control the pressure of fluid in said connectingmeans in a disengaged condition of said system and said at least oneselector valve being arranged to determine the selection of a gear bysaid regulating means in said disengaged condition of said system. 2.The motor vehicle of claim 1, wherein said system includes an automatedfriction clutch.
 3. The motor vehicle of claim 1, wherein saidregulating means includes at least one valve.
 4. The motor vehicle ofclaim 1, wherein said operating means and said unit together constitutea unitary module.
 5. The motor vehicle of claim 1, wherein saidoperating means and said unit respectively constitute separate first andsecond modules and said connecting means includes at least one conduitarranged to establish a path for the flow of fluid between said modules.6. The motor vehicle of claim 1, wherein said system comprises at leastone cylinder and said operating means comprises at least one adjustablevalve and a conduit connecting said valve with said at least onecylinder.
 7. The motor vehicle of claim 1, wherein said system includesa mobile engaging/disengaging element and said regulating means includesat least one gear selecting/shifting element, one of said unit and saidoperating means comprising at least one device for monitoring the extentof movement of at least one of said elements.
 8. The motor vehicle ofclaim 1, wherein said regulating means includes at least one mobile gearselecting/shifting element and said regulating means comprises at leastone device for monitoring the extent of movement of said at least oneelement.
 9. The motor vehicle of claim 1, wherein said regulating andoperating means ana said unit respectively constitute separate first andsecond modules and said connecting means comprises at least one conduitconnecting said modules, said system including a mobileengaging/disengaging element and said regulating means including amobile gear selecting/shifting element, said operating means comprisinga first device for monitoring the extent of movement of saidengaging/disengaging element and said regulating means comprising asecond device for monitoring the extent of movement of said gearselecting/shifting element.
 10. The motor vehicle of claim 1, whereinsaid system includes a mobile engaging/disengaging element and saidtransmission comprises at least one mobile gear selecting/shiftingelement, and further comprising a conduit connecting said operatingmeans with said mobile engaging/disengaging element, said operatingmeans including at least one first proportional valve and saidregulating means including at least one second proportional valve insaid connecting means.
 11. The motor vehicle of claim 10, furthercomprising at least one selector valve provided downstream of therespective proportional valve as seen in the direction of fluid flowfrom said source.
 12. The motor vehicle of claim 1, wherein said systemincludes a mobile engaging/disengaging element and said transmissionincludes a mobile gear selecting element and a mobile gear shiftingelement, at least one of said operating means and said regulating meanscomprising at least one proportional valve.
 13. The motor vehicle ofclaim 12, wherein said at least one proportional valve is disposed in aconduit connecting said source with said engaging/disengaging element.14. The motor vehicle of claim 12, wherein said proportional valve isinstalled in said connecting means between said source and said gearselecting element.
 15. The motor vehicle of claim 12, wherein saidproportional valve is installed in said connecting means between saidsource and said gear shifting element.
 16. The motor vehicle of claim 1,wherein at least one of said operating means and said regulating meanscomprises at least one adjustable selector valve.
 17. The motor vehicleof claim 1, wherein said system includes a mobile engaging/disengagingelement and said transmission includes at least one mobile gearselecting/shifting element, and further comprising at least one conduitconnecting said operating means with said system, at least one of saidregulating and said operating means comprising at least one proportionalvalve installed in one of said at least one conduit and said connectingmeans.
 18. The motor vehicle of claim 17, wherein said at least one ofsaid regulating and said operating means further comprises an adjustableselector valve disposed downstream of said at least one proportionalvalve as considered in the direction of fluid flow from said source. 19.The motor vehicle of claim 17, further comprising an adjustable selectorvalve in the other of said at least one conduit and said connectingmeans.
 20. The motor vehicle of claim 1, wherein said system comprises amobile engaging/disengaging element and said transmission comprises amobile gear selecting element and a mobile gear shifting element, saidoperating means comprising at least one first proportional valve in aconduit connecting said source with said engaging/disengaging elementand said regulating means comprising at least one second proportionalvalve provided in said connecting means for said gear shifting element.21. The motor vehicle of claim 20, further comprising at least oneselector valve for at least one of said proportional valves, said atleast one selector valve being disposed downstream of the respectiveproportional valve as considered in the direction of fluid flow fromsaid source.
 22. The motor vehicle of claim 1, wherein said regulatingmeans comprises a differential cylinder provided in said connectingmeans and having first and second cylinder chambers, at least oneproportional valve provided in said connecting means upstream of saidcylinder as considered in the direction of fluid flow from said source,and first and second selector valves provided in said connecting meansdownstream of said at least one proportional valve to respectivelydetermine the flow of fluid to and from and the pressure of fluid insaid first and second cylinder chambers, said cylinder including amobile piston disposed between said chambers to determine the shiftinginto a selected gear in dependency upon the differential of fluidpressures in said chambers.
 23. The motor vehicle of claim 22, whereinsaid regulating means includes means for adjusting said selector valvesso that (a) the pressure of fluid in one of said chambers at leastapproximates the pressure of fluid in the other of said chambers, (b)the pressure of fluid in at least one of said chambers is at least closeto zero, and (c) the pressure of fluid in one of said chambers is higherthan the pressure of fluid in the other of said chambers.
 24. The motorvehicle of claim 23, wherein said regulating means includes means forestablishing a plurality of differences between the pressures of fluidin said chambers, at least for each of said plurality of gears.
 25. Themotor vehicle of claim 1, wherein said regulating means comprises adifferential cylinder provided in said connecting means and having firstand second cylinder chambers, at least one proportional valve providedin said connecting means upstream of said cylinder as considered in thedirection of fluid flow from said source, and first and secondadjustable selector valves provided in said connecting means downstreamof said at least one proportional valve to respectively determine theflow of fluid to and from and the pressure of fluid in said first andsecond cylinder chambers, said cylinder including a mobile pistondisposed between said chambers to determine the selection of gears independency upon the differential of fluid pressures in said chambers.26. The motor vehicle of claim 25, wherein said at least oneproportional valve is adjustable to control the pressure of fluid insaid connecting means between said at least one proportional valve andsaid selector valves.
 27. The motor vehicle of claim 26, wherein said atleast one proportional valve is a slide spool valve.
 28. The motorvehicle of claim 26, wherein said at least one valve is a directionalcontrol valve.
 29. The motor vehicle of claim 26, wherein said at leastone proportional valve is a pressure reducing valve.
 30. The motorvehicle of claim 29, wherein said pressure reducing valve is afeedback-operated valve.
 31. The motor vehicle of claim 1, wherein atleast one of said operating means and said regulating means comprises atleast one differential cylinder having first and second cylinderchambers and being disposed in said connecting means to shift saidtransmission into a selected gear in dependency upon the relationship offluid pressures in said chambers and the position of at least one mobilepiston provided in said at least one cylinder between said chambers. 32.The motor vehicle of claim 31, wherein said regulating means furthercomprises at least one selector valve for the determination of forcesacting upon said at least one piston in dependency upon the pressures offluid in said chambers.
 33. A motor vehicle comprising an engine; atransmission shiftable into selected ones of a plurality of gears; anengageable and disengageable torque transmitting system in a path forthe flow of torque between said engine and said transmission; and anoperating unit for initiating changes in the extent of engagement ofsaid system and a shifting of said transmission into selected gears tothus effect an automated gear change, said operating unit being arrangedto receive a pressurized flowable medium by a hydraulic unit having apump and an accumulator, said operating unit comprising at least oneoperating member and said hydraulic unit further comprising valves andhydraulic connections arranged to carry out controlled gear selectingand shifting operations, said operating and hydraulic units comprising afirst section in which a proportional valve controls a fluid pressurefor shifting said transmission by way of a second operating member and asecond valve downstream of said proportional valve is arranged to selectthe shifting direction, said operating and hydraulic units furthercomprising a second section wherein a proportional valve controls afluid pressure for the actuation of said system by means of said atleast one operating member and for the selection of a gear by a thirdoperating member, at least one additional valve downstream of saidproportional valve in said second section being arranged to initiate theselection of a gear.
 34. A motor vehicle comprising an engine; atransmission shiftable into a plurality of gears; an engageable anddisengageable torque transmitting system in a torque transmitting pathbetween said engine and said transmission; and a hydraulic unitincluding a pump and at least one valve for operation of a hydrauliccylinder arranged to control the torque adapted to be transmitted bysaid torque transmitting system along an engaging/disengaging path, thedisengagement of said torque transmitting system being monitored by asensor which is disposed in a fluid conveying connection to an operatingmember for said torque transmitting system and comprises a piston which,by its position relative to a sensor, denotes the extent ofdisengagement of said torque transmitting system.
 35. The motor vehicleof claim 34, wherein said piston is axially movably mounted in ahousing, at least one side of said piston being acted upon by at leastone spring disposed in said housing, discrete plenum chambers beingdisposed in front of and behind said piston, as seen in an axialdirection of said piston, said plenum chambers being provided withhydraulic connections and said sensor being arranged to monitor theaxial position of said piston, a controlled actuation of said torquetransmitting system bringing about an axial displacement of said piston.36. A motor vehicle comprising an engine; a transmission shiftable intoselected ones of a plurality of gears; an engageable and disengageabletorque transmitting system in a path for the flow of torque between saidengine and said transmission; and an operating unit for initiatingchanges in the extent of engagement of said system and a shifting ofsaid transmission into selected gears to thus effect an automated gearchange, said operating unit being arranged to receive a pressurizedflowable medium by a hydraulic unit having a pump and an accumulator,said operating unit comprising at least one operating member and saidhydraulic unit further comprising valves and hydraulic connectionsarranged to carry out controlled gear selecting and shifting operations,said operating and hydraulic units comprising a first section in which aproportional valve controls a fluid pressure for the torque transmittingsystem, said operating and hydraulic units further comprising a secondsection wherein a proportional valve controls a fluid pressure for theactuation of said system by means of one operating member, saidoperating and hydraulic units further comprising a third section for theselection of a gear by a third operating member, at least one additionalvalve downstream of one of a hydraulic resistance and a pressurereducing valve in said third section being arranged to initiate theselection of a gear.